arm/arm64: KVM: fix potential NULL dereference in user_mem_abort()

Handle the potential NULL return value of find_vma_intersection()
before dereferencing it.

Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 8f0c7a4c49fc..bb2e110e77c0 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -776,6 +776,12 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
         /* Let's check if we will get back a huge page backed by hugetlbfs */
         down_read(&current->mm->mmap_sem);
         vma = find_vma_intersection(current->mm, hva, hva + 1);
+        if (unlikely(!vma)) {
+                kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
+                up_read(&current->mm->mmap_sem);
+                return -EFAULT;
+        }
+
         if (is_vm_hugetlb_page(vma)) {
                 hugetlb = true;
                 gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT;